This link will assist you in how a dealer appraises your vehicle when you trade it in. If your having trouble deciding whether you should repair those dents and scratches look at this guideline. One of the major differences between excellent and good condition is if the vehicle is free of visible defects. If you take the car in with minor scratches or dents it could downgrade the vehicle grade. Have them repaired before the trade so you can maximize your trade in value.
http://auto.howstuffworks.com/buying-selling/kelley-blue-book4.htm
http://auto.howstuffworks.com/buying-selling/kelley-blue-book4.htm